Anatomically Oriented Right Ventricular Volume Measurements With Dynamic Three-Dimensional Echocardiography Validated by 3-Tesla Magnetic Resonance Imaging

ObjectivesWe tested a newly developed 4-dimensional (4D) right ventricular (RV) analysis method for computing RV volumes for both 3-dimensional (3D) ultrasound (US) and magnetic resonance (MR) images.BackgroundAsymmetry and the anatomical complexity of the RV make accurate determination of RV shape and volume difficult.MethodsThirty patients, 14 with grossly normal cardiac anatomy and 16 with major congenital heart disease, were studied at the same visit with both 3D echocardiography (echo) and magnetic resonance imaging (MRI) for RV size and function. Ultrasound images were acquired on a Philips 7500 system (Philips Medical Systems, Andover, Massachusetts) with a matrix-array transducer (real-time 3D echo) with full volume sweeps from apical and subcostal views. Sagittal, 4-chamber, and coronal views were derived for contour detection (all 12 to 24 slices). The MR images were acquired with a 3-T MRI magnet with segmented cine-loop gradient echo sequences in short- and rotated long-axis views to cover the RV inflow, body, and outflow tract. The RV volumes were analyzed with the new software applicable to 3D echo MR images.ResultsNew software aided delineation of the RV free wall, tricuspid valve, RV outflow tract, and apex on 3D echo volumes. Although there was a slightly higher variability measuring right ventricular ejection fraction (RVEF) and volumes obtained by US compared with MRI, both imaging methods showed closely correlated results. The RVEF was measured with 4% variability for US and 5% variability for MRI with a correlation coefficient of r = 0.91. The RV end-diastolic volume was measured at 70.97 ± 15.0 ml with 3D US and at 70.06 ± 14.8 ml with MRI (r = 0.99), end-systolic volume measured 39.8 ± 10.4 ml with 3D US and 39.1 ± 10.2 ml with MRI (r = 0.98).ConclusionsThe new RV analysis software allowed validation of the accuracy of 4D echo RV volume data compared with MRI.